text: It depends upon how far along you are. Also, what sort of books you're reading. stjep assumed you were reading adult books. But you could start with baby books and learn referents (the objects that pair with words) that way, and then advance. If you did that, I see no reason why you couldn't learn a lot more about the language, though of course, you'd need more than just written exposure to obtain fluency. Speaking in conversations forces you to think and act faster than reading, which you can do at your own pace, and forces improvement.